Access control systems may use one or more authentication factors to verify an individual's identity. For example, authentication factors may include “something-you-know,” “something-you-have,” and “something-you-are.” Some access control systems may require elements from two or three of these categories to provide two or three-factor authentication.
Biometrics may provide the “something-you-are” factor used for identification and authentication. Biometrics can be coupled with other categories of factors, such as “something-you-have,” and “something-you-know,” to achieve two and three-factor authentication when greater assurance is required than a single factor can provide. Biometric traits may include, for example, biological (e.g., fingerprint, iris, hand geometry, etc.) and behavioral (e.g., gait, gesture, keystroke dynamics, etc.) characteristics that reliably distinguish one person from another.